scholarly journals Four-dimensional de Sitter space is a Glauber-Sudarshan state in string theory

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Suddhasattwa Brahma ◽  
Keshav Dasgupta ◽  
Radu Tatar
Keyword(s):  
String Theory ◽  
Coherent State ◽  
Degrees Of Freedom ◽  
Vacuum Energy ◽  
De Sitter Space ◽  
The Other ◽  
Quantum Corrections ◽  
De Sitter ◽  
Other Hand

Abstract We show that four-dimensional de Sitter space is a Glauber-Sudarshan state, i.e. a coherent state, over a supersymmetric solitonic background in full string theory. We argue that such a state is only realized in the presence of temporally varying degrees of freedom and after including quantum corrections, with supersymmetry being broken spontaneously. On the other hand, fluctuations over the resulting de Sitter space is governed by the Agarwal-Tara state, which is a graviton (and flux)-added coherent state. Once de Sitter space is realized as a coherent state, and not as a vacuum, its ability to remain out of the swampland as well as issues regarding its (meta)stability, vacuum energy, and finite entropy appear to have clear resolutions.

scholarly journals de Sitter space as a Glauber-Sudarshan state

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Suddhasattwa Brahma ◽  
Keshav Dasgupta ◽  
Radu Tatar
Keyword(s):  
Coherent State ◽  
Degrees Of Freedom ◽  
Zero Point ◽  
De Sitter Space ◽  
Configuration Spaces ◽  
Quantum Field Theories ◽  
De Sitter ◽  
Point Energy ◽  
Classical Trajectories ◽  
Entropy Zero

Abstract Glauber-Sudarshan states, sometimes simply referred to as Glauber states, or alternatively as coherent and squeezed-coherent states, are interesting states in the configuration spaces of any quantum field theories, that closely resemble classical trajectories in space-time. In this paper, we identify four-dimensional de Sitter space as a coherent state over a supersymmetric Minkowski vacuum. Although such an identification is not new, what is new however is the claim that this is realizable in full string theory, but only in conjunction with temporally varying degrees of freedom and quantum corrections resulting from them. Furthermore, fluctuations over the de Sitter space is governed by a generalized graviton (and flux)-added coherent state, also known as the Agarwal-Tara state. The realization of de Sitter space as a state, and not as a vacuum, resolves many issues associated with its entropy, zero-point energy and trans-Planckian censorship, amongst other things.

HOLOGRAPHIC SPACETIME

2012 ◽  
Vol 21 (11) ◽  
pp. 1241004 ◽  
Author(s):  
TOM BANKS
Keyword(s):  
String Theory ◽  
Degrees Of Freedom ◽  
Good Description ◽  
De Sitter ◽  
Finite Radius ◽  
Full Field ◽  
Mass Scaling ◽  
Finite Dimensional ◽  
Emergent Phenomena ◽  
Holographic Screen

The theory of holographic spacetime (HST) generalizes both string theory and quantum field theory (QFT). It provides a geometric rationale for supersymmetry (SUSY) and a formalism in which super-Poincare invariance follows from Poincare invariance. HST unifies particles and black holes, realizing both as excitations of noncommutative geometrical variables on a holographic screen. Compact extra dimensions are interpreted as finite-dimensional unitary representations of super-algebras, and have no moduli. Full field theoretic Fock spaces, and continuous moduli are both emergent phenomena of super-Poincare invariant limits in which the number of holographic degrees of freedom goes to infinity. Finite radius de Sitter (dS) spaces have no moduli, and break SUSY with a gravitino mass scaling like Λ1/4. In regimes where the Covariant Entropy Bound is saturated, QFT is not a good description in HST, and inflation is such a regime. Following ideas of Jacobson, the gravitational and inflaton fields are emergent classical variables, describing the geometry of an underlying HST model, rather than "fields associated with a microscopic string theory". The phrase in quotes is meaningless in the HST formalism, except in asymptotically flat and AdS spacetimes, and some relatives of these.

scholarly journals THE FORMATION OF PROFESSIONAL TALENT IN DETERMINATION WITH SEMANTIC ATTITUDE TO INNOVATIONS UNDER THE INFLUENCE OF VARIOUS DEGREES OF FREEDOM IN ACTIVITY

2020 ◽  
Vol 17 (4) ◽  
pp. 91-101
Author(s):  
T.N. Soboleva ◽  
Keyword(s):  
Empirical Data ◽  
Degrees Of Freedom ◽  
The Other ◽  
Psychological Analysis ◽  
Other Hand ◽  
Professional Talent ◽  
The One ◽  
The Impact ◽  
Three Degrees Of Freedom

The article is devoted to the poorly studied problem of the formation of talent in the conditions of different degrees of freedom in activity and the impact on that formation of a person’s conservative and innovative semantic attitudes towards the introduction of new equipment. The main objective of the study is to describe how the conditions of different degrees of freedom in the activity are refracted with internal conditions, which are conservative and innovative semantic attitudes and various talent structures. The study was conducted on a sample of 54 qualified railway drivers using a specialized simulator which allows to simulate three degrees of freedom in the activity. The psychological analysis of the activity revealed seven abilities ensuring the implementation of the activity. Based on empirical data, the article shows that low, medium and high degrees of freedom in activity are manifested in different degrees of productivity. Conservative and innovative semantic attitudes to the introduction of new equipment do not have a significant effect on the productivity of the activity in the conditions of different degrees of freedom. Along with this, depending on the conservative and innovative semantic attitudes, different structures of talent in terms of composition and degree of integration under the conditions of different degrees of freedom in the activity are formed. On the one hand, conservative and innovative semantic attitudes act as internal determinants; on the other hand, low, medium and high degrees of freedom in the activity act as external determinants of the formation of various talent structures.

scholarly journals Hybrid inflation and waterfall field in string theory from D7-branes

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Ignatios Antoniadis ◽  
Osmin Lacombe ◽  
George K. Leontaris
Keyword(s):  
String Theory ◽  
Flux Compactifications ◽  
Saddle Point ◽  
Present State ◽  
Global Minimum ◽  
Vacuum Energy ◽  
De Sitter ◽  
Hybrid Inflation ◽  
De Sitter Vacuum ◽  
The Universe

Abstract We present an explicit string realisation of a cosmological inflationary scenario we proposed recently within the framework of type IIB flux compactifications in the presence of three magnetised D7-brane stacks. Inflation takes place around a metastable de Sitter vacuum. The inflaton is identified with the volume modulus and has a potential with a very shallow minimum near the maximum. Inflation ends due to the presence of “waterfall” fields that drive the evolution of the Universe from a nearby saddle point towards a global minimum with tuneable vacuum energy describing the present state of our Universe.

scholarly journals De Sitter entropy as holographic entanglement entropy

2021 ◽  
Author(s):  
Nikolaos Tetradis
Keyword(s):  
Effective Action ◽  
Degrees Of Freedom ◽  
Entanglement Entropy ◽  
De Sitter Space ◽  
Conformal Anomaly ◽  
Dual Theory ◽  
De Sitter ◽  
Logarithmic Corrections ◽  
Holographic Entanglement Entropy ◽  
Gravitational Entropy

We review the results of refs. [1,2], in which the entanglement entropy in spaces with horizons, such as Rindler or de Sitter space, is computed using holography. This is achieved through an appropriate slicing of anti-de Sitter space and the implementation of a UV cutoff. When the entangling surface coincides with the horizon of the boundary metric, the entanglement entropy can be identified with the standard gravitational entropy of the space. For this to hold, the effective Newton's constant must be defined appropriately by absorbing the UV cutoff. Conversely, the UV cutoff can be expressed in terms of the effective Planck mass and the number of degrees of freedom of the dual theory. For de Sitter space, the entropy is equal to the Wald entropy for an effective action that includes the higher-curvature terms associated with the conformal anomaly. The entanglement entropy takes the expected form of the de Sitter entropy, including logarithmic corrections.

scholarly journals EXPONENTIAL LAGRANGIAN FOR THE GRAVITATIONAL FIELD AND THE PROBLEM OF VACUUM ENERGY

2008 ◽  
Vol 23 (08) ◽  
pp. 1286-1289 ◽  
Author(s):  
ORCHIDEA MARIA LECIAN ◽  
GIOVANNI MONTANI
Keyword(s):  
Gravitational Field ◽  
Cosmological Constant ◽  
Lagrangian Density ◽  
Vacuum Energy ◽  
The Other ◽  
Present Value ◽  
Other Hand ◽  
Free Parameters ◽  
The One

We will analyze two particular features of an exponential gravitational Lagrangian. On the one hand, while this choice of the Lagrangian density allows for two free parameters, only one scale, the cosmological constant, arises as fundamental when the proper Einsteinian limit is to be recovered. On the other hand, the vacuum energy arising from f(R) theories such that f(0) ≠ 0 needs a cancellation mechanism, by which the present value of the cosmological constant can be recast.

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